A facile approach for acid mine drainage treatment by the formation of Fe–Mn layered double hydroxide

Heavy metal and sulfate ions pollution already threaten aquatic ecosystems around the world, and acid mine drainage (AMD) is currently the main pollutant of surface water and underground water. It is a major challenge to simultaneously remove anions and cations from AMD without vast quantities of sludge. We propose a facile approach for the removal of Fe³⁺, Mn²⁺, and SO₄²⁻ from acid mine drainage by the formation of Fe–Mn layered double hydroxide (LDH) intercalated with SO₄²⁻ in one step. This study investigated the effects of the method of reactants’ addition, nitrogen gas protection, reaction time, pH value, and different molar ratios of Fe³⁺/Mn²⁺ on the removal ratios of these ions. The highest removal ratios of Fe³⁺, Mn²⁺, and SO₄²⁻ were 99.99%, 99.95%, and 48.33%, respectively. More importantly, the product Fe–Mn LDH is of great adsorptive performance for As (III), with a removal ratio of 93.08%. This approach was feasible and suitable for AMD containing a high concentration of Fe³⁺ and Mn²⁺. This AMD treatment by the formation of Fe–Mn LDH can achieve resource utilization of AMD, which is a promising AMD treatment method.